Signaling system



16, 1940. Q v, THORP 2,187,104

SIGNALING SYSTEM Filed Feb. 11, 1939 PHILADELPHIA FIG. 2

MARG/NA L SLOW SLOW OPERATING RELEA SING lNl/EN 70/? I K P. THORP BY A 7' TORNEV Patented Jan. 16, 1940 I a i I I Q.

UNITED I STATES P TEN OFFICE SIGNALING SYSTEM Vaughn P. 'Thor'p, Hohokus, N. J., assignor to Bell Telephone Laboratories, Incorporated, New a York, N. Y., acorporation of New York Application February 11, 1939, Serial No. 255,814-

6 Claims. (Cl. 178-2) This invention relates to telegraph systems and acting quick-releasing vacuum tube circuit unparticularly to systems wherein a common transresponsive to incoming signals oinormal length mission channel is provided for a plurality of stabut responsive to signals of abnormal length. such tions, any one of which may broadcast messages as break signals or other prolonged open cirinto said channel for simultaneous reception by cuit conditions. 5-

all of said stations. The invention is an improve- In the drawing, ment on the system disclosed in Patent 2,111,684 Fig.1 is a schematic representation of the comgrantedMarch 22, 1938- to C. R. Walker and is a plete system in which the invention is employed; specificimprovement in the system disclosed in and I the application of Branson et a1. Ser. No. 255,820 Fig. 2 is a circuit diagram showing the details of 10 filed on Feb. 11, 1939. a station circuit embodying the present invention. In ring type circuits having even a measurable In'Fig, 1 there is shown a ring circuit including 7 propagation time, signals transmitted from one rectangles l, 2, 3, 4, 5jand fi'which represent stastation in .the ring will traverse the ring and retion circuits at as many different cities, such,- for turnto that station at a later time. Since our instance, as New York, Boston-Albany, Bufialo, 15

signals at the outgoing terminalsbf the station Pittsburgh and Philadelphia. There is also and the same signals atthe incoming terminals shown in thecircuit a rectangle l and another of the same station are not in synchronism it folrectangle 8 which may indicate repeaters or other lows that thecircuit at such station must be time consuming transmission apparatus. To

broken in order to avoid interference, The .outeach station circuit at the different points in the 9 going and incoming terminalsof the transmitring one or more separate'subscriber stations may ting station .must be separated. Hence, during be connected. The transmitting contacts 9 and transmission the normally closed connection bethe magnet Hi represent in the usual form a sub tween the incoming and outgoing terminals'of scribers teletypewriter station. The transmit- 5 the station circuit must be'automatically opened. ting contacts II and the magnet l2 represent a Moreover, this open condition must be mainsimilar subscribers station connected to the same tained for a period longer than the propagation station circuit l. i time of the ring to prevent closure until after the In Fig. 2, conductors l3 and i4 represents the last impulse has completely traversed the circuit incoming terminal and marking and spacing cur- 0 in order to prevent the establishment of a travelrents in these conductors cause the relay 15 to 39 ing impulse which might otherwise continue to move its armature either to its marking or spactraversethe ring indefinitely; Thus a slow-re ing contact. Under normal conditions, marking leasing means for opening the normal connection and spacing impulses received by the relay l5 etwe the incoming a g g terminals is will be transmitted over the conductor l6 through provided and m dezresp n ive o mpulses from the back'contact and armature of relay H, the the-station tra i g pp at s An jec back contact and armature of relay lBto the apex of the pr t invention is o mp v i I the of the windings of relay I9, thence over the sub-' meansheretofore: used to perform this function ribe stations 20' and 2| and the winding of yp v ine l s xp s v m re ely p rtransmitting relay 22 to ground.' Relay 19 does 0 ailing and adjustable pp Accordingly, not respond to this circuit and hence the trans- 4Q feature of this invention is a quick-acting slowmission coming in on conductgrs [3 and [4' will releasing vacuum tube circuit Whose releasin be repeated over conductors 23 and 24, represent- .time be QQ'CCIfUatEIY and easily adjusted to ing the outgoing terminal of this station circuit. bea definlte time interval longer than the propa- Relay 25 follows Signals coming in over gation time of the particular ring circuit in which ductors g3 and M and is Operated when relay '5 it i to s S be u 8 goes to its spacing contact. Smceunder normal Another object of the invention is to provide improved means t0 respond to break Signals for telegraph signal transmission conditions relay l5 notifying a transmitting operator that use of. does not remain for any greatlength of time on .50 the circuit is desired by another and to antomatiits Spacing ct, relay 25. does not remove 5O cally close through the-normal connection betery'from the grid 1 anyilength of tween the incoming and outgoing terminals which tlme- The grid of this tube being k p ve, has been opened in response to the operation of (1098 not BJIQW p e current W of Silfiiclent the transmitting apparatus. value to operate either relay l'l or l8. Through Another-feature of the invention then; is a slow the resistance 2'! and capacity 28 and the normal 55 a connection of the grid to positive battery the tube 26 is effectively rendered a slow-operating relay.

When either subscribers station 20 or 2| is transmitting both relays I9 and 22 respond. Relay 22 by opening and closing the connection between the outgoing conductors 23 and 24 effectively relays the code impulses sent by one of the subscribers stations 20 or 2|. The armature of relay I9 moves to its spacing contact in response to spacing impulses and during these short intervals places battery on the grid of tube 29 which through the resistance 30 and condenser 3| efiectively becomes a slow-releasing relay. Therefore, under normal transmission from either subscriber's station 20 or 2|, tube 29 will deliver enough current to conductor 32 to cause the operation of relay II, which effectively opens the line from the incoming terminals and places marking battery through its front contact and armature and the back contact and armature of marginal relay I8 to the apex of the coils of relay I9. This marking battery renders it possible for subscribers station 20 or station 2| to trans mit uninterruptedly unless a long break signal is received.

The characteristic of the vacuum tube 29 is such that after subscribers station 29 or 2| has ceased to transmit, the relay I! will be held operated for a period somewhat greater than the propagation time of the entire ring.

If while either subscribers station 20 or 2| is transmitting, a break is made in the ring circuit so that a permanent spacing signal appears on conductors I3 and I4 then relay 25 in responding for a period longer than normal will allow vac uum tube 26 to transmit enough additional current in conductor 32 to cause the operation of marginal relay I8, whereupon a spacing signal is connected from the armature of relay I5 to the front contact and armature of relay I8 to the apex of the coils of relay I9. This will appear in the subscribers stations 2|! and 2| as a spacing signal and the operator thereat will accordingly cease transmitting. Relay I9 going to its marking contact will deenergize the tube 29 so that in a period somewhat greater than the propagation time of the circuit this tube will cease to supply current to conductor 32. When vacuum tube 29 ceases to function, the current supplied by vacuum tube 26 becomes only suiiicient to hold relay II operated and marginal relay I8 thereupon deenergizes. Thereupon marking battery through the front contact and armature of relay I1 is again connected to the back contact and armature of relay I8 to the apex of the coils of relay I9 and thus marking current manifests itself as marking signals in subscribers stations 20 and 2| and affects the relay 22 to transmit a marking signal into the ring circuit beyond. In time this marking signal appears in the receiver of the breaking station and this station thereupon goes on with its transmission. As soon as marking signal appears on conductors I3 and I4 relay 25 will again place negative battery on the grid of tube 26, causing the release of relay I1 and restoring the circuit to its normal condition.

Thus vacuum tube 29 constitutes a quick-acting and slow-releasing means responsive to transmission from a local station for opening the ring in this station circuit. Vacuum tube 26 constitutes a slow-operating and quick-releasing means for controlling the station circuit in response to break signals and other prolonged open-circuit conditions manifesting themselves on the incoming terminal conductors I3 and I4.

Subscribers stations 20 and 2| are shown differently. Subscribers station 20 has its transmitting and receiving apparatus both in the same subscriber station loop while subscribers station 2| has a separate loop for each. Thus, if it is desired to receive a record of what is transmitted from subscribers station 2| after the signals have traversed the entire ring then the receiving device represented by the receiving magnet 33 is connected to the incoming terminal and this device, while cut off from the transmitting apparatus locally, will be of utility in proving the continuity of the circuit.

It should further be noted that a simultaneous two-way conversation can be carried on between two stations such, for instance, as between New York and Buffalo, in Fig. 1. In this case while'subscribcrs station 2| is transmitting from New York to Buffalo, this message being received also by Boston and Albany, Bufialo may be transmitting to New York, the Bufialo message being received on the device 33 as well as at Pittsburgh and Philadelphia. Such a connection is spoken of by telegraphers operating this type of facility as a two-way conversation because from the operating standpoint the effect is the same as two-way communication over the same circuit as in duplex and other well-known types of system. Actually, the transmission from New York to Buffalo in the example given is over an entirely different circuit, including the Boston and Albany stations, than the transmission from Bufialo to New York which includes the Pittsburgh and Philadelphia stations. Since, while the operator at New York is transmitting, his station circuit is efiectively opened so as not to repeat incoming signals he may receive one message from Buffalo while at the same time he is transmittin an entirely different message to Buffalo, and the same effect holds at Buffalo. In other words, when this is done with the aid of equipment shown in Fig. 2 both at New York and at Bufialo, the ring in effect becomes disrupted and two independent one-way circuits are established.

Further, it is possible, due to this automatic separation of the incoming and outgoing terminals in a station circuit, for one message to be transmitted from a first to a second station, such as from New York to Boston in Fig. 1, another from a second to a third station, such as from Boston to Albany in Fig. 1, another from a third to a fourth or a fifth station, such as from Albany to Bufialo or Pittsburgh in Fig. 1, and so on. It will be appreciated that the system is flexible and capable of being operated in a variety of ways, all consistent with the incoming terminals being effectively connected to the outgoing terminals under normal conditions and with this connection broken when signals are being transmitted What is claimed is:

1. In a signaling system, a station circuit having incoming and outgoing terminals normally connected for through transmission, transmitting apparatus associated with said outgoing terminal, means for opening said normal connection between said terminals and a quick-operating slowreleasing vacuum tube circuit responsive to signals from said transmitting apparatus for operatin said means.

2. In a signaling system, a station circuit having incoming and outgoing terminals normally connected for through transmission, receiving apparatus connected to said incoming terminal, transmitting apparatus associated with said out- "apparatus associated with said outgoing terminal,

means for opening said normal connection between said terminals, a quick-acting slow-releasing means responsive to signals from said transmitting apparatus for operating said means and a slow-acting quick-releasing vacuum tube circuit responsive to signals received over said incoming terminal for closing said normal connection between said terminals when opened by said means.

4. In a signaling system, a station circuit having incoming and outgoing terminals normally connected for through transmission, transmitting apparatus associated with said outgoing terminal, means for opening said normal connection between said terminals, a quick-acting slow-releasing vacuum tube, circuit responsive to signals from said transmitting apparatus for operating said means, and a slow-acting quick-releasing vacuum tube circuit responsive to signals received over said incoming terminal for closing said normal connection between said terminals who opened by saidmeans.

'5. In a signaling system, a station circuit having incoming and outgoing terminals'normally connected for through transmission, transmitting apparatus associated with said outgoing terminal, means for opening said normal connection between said terminals, a'quick-acting slow-releasing vacuum tube circuit responsive to signals from said transmitting apparatus for operating said means, and a vacuum tube circuit unresponsive to normal signals and responsive to abnormal signals received over said incoming terminal for closing said normal connection between said terminals when opened by said means.

'6. Ina signaling system, a station circuit having incoming and outgoing terminals normally connected for through transmission, transmitting apparatus associated with said outgoing terminal, means for opening said normal connection between said terminals, a quick-acting slow-releasing vacuum tube circuit responsive to signals from said transmitting apparatus for operating said means and a slow-acting quick-releasing vacuum tube circuit responsive only to signals of abnormal length received over said incoming terminal for releasing said means.

VAUGHN P. THORP, 

